Satellite Observations of the Elephant Butte Reservoir in New Mexico (USA) Max P. Bleiweiss(1), Thomas Schmugge(2) , William L. Stein(3) (1)Dept. of Entomology, Plant Pathology & Weed Science, New Mexico State Univ. PO Box 30003, MSC 3BE, Las Cruces, New Mexico 88003 USA
[email protected] (2)College of Agriculture, New Mexico State University PO Box 30003, MSC 3AG, Las Cruces, New Mexico 88003 USA
[email protected] (3)Physical Science Laboratory, New Mexico State University PO Box 30002, Las Cruces, New Mexico 88003 USA,
[email protected] ABSTRACT Since the launch of NASA's Terra satellite in December 1999, the Advanced Spaceborne Thermal Emission and Reflection (ASTER) instrument has made a number of observations of the Elephant Butte Reservoir. The first observations were in June 2000 and the most recent were in October 2007. This period includes the recent drought conditions and the earlier full water conditions. The area of the reservoir was estimated for each of these scenes and compared with known water levels. The ASTER observations include both the visible reflectance and the thermal infrared emission (surface temperature). Both spectral regions can provide good contrast between the water and the surrounding land. This contrast makes the area estimation straightforward. INTRODUCTION For many reservoirs there are considerable fluctuations in levels as water is drawn down for irrigation purposes. We present satellite observations of changes in the surface water area as evidence of this drawdown. Since the launch of NASA's Terra satellite in December 1999, ASTER has made more than 30 observations of the Elephant Butte Reservoir located on the Rio Grande in central New Mexico, USA including night-time observations.